The French word l'eau means water in the singular. But what does it mean in the plural? In English, if we say "waters", we typically refer to bodies of water like seas, lakes, or oceans. Does it have the same meaning in French? If not, what does it mean?

Varieties of water, bodies of water, instances of water (to boil down what has been said, hopefully comprehensibly). I summarize it this way because that's a frequent function of the plural for mass nouns.
– Luke SawczakSep 19 '17 at 11:00

does "waters" really refer to bodies of water in English?
– martin jakubikSep 19 '17 at 15:29

@martinjakubik Not often, but see for example Genesis 7:18.
– ktm5124Sep 19 '17 at 15:36

@martinjakubik Or this NBC headline: "The world's most pirate-infested waters".
– ktm5124Sep 19 '17 at 15:38

yeah, I'll take the NBC one :) wiktionary has some examples too. You're right it's definitely used, but offhand I would say it comes up in different contexts in English than les eaux in French.
– martin jakubikSep 19 '17 at 15:41